Stacking of integrated circuits has long been an available technique for increasing functionality for a given amount of space. For example, this has been a technique for doubling the amount of memory by stacking two memory integrated circuits. It has now become more desirable to used stacked integrated circuits that are of a different type not just because of the increased density available without requiring a single die, but also because of the different manufacturing techniques used for the different functions. For example, rf circuits often needed to be used in conjunction with logic circuits but the manufacturing techniques are quite different for these different functions. Thus, it is more practical to stack these two functions than try to achieve them both on the same integrated circuit. In stacking die, issues arise relating to the interconnection between die that are not present with regard to a single die. One example is that it is helpful when stacking die to have a contact on the backside, the side opposite of where the circuitry is formed, of the die.
Therefore, what is needed is an improved method for manufacturing a die with a backside contact.